| A dollar just happens to be cut into 100 slices. | ||
| What if it wasn't? | ||
| There is nothing so special about a number | ||
| with 2 places on the right side of the decimal point. | ||
| If our a dollar was cut up into 1000 pieces, | ||
| we would need 3 number places | ||
| (called decimal places in fancy math talk) | ||
| on the right side: | ||
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$1.000 |
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| We could still add this stuff up the same way. | ||
| Just remember that the decimal point on all numbers MUST line up: | ||
| Examples: | ||
| Add .391 and .608 ... | ||
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| Subtract .206 from .978 ... | ||
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| In fact, we could have any number of places | ||
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on the right of the decimal point: |
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| Examples: | ||
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| What happens if we have 2 numbers to add that look like this: | ||
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.3157 + .23 |
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| First, we line up the decimal points: | ||
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| WAIT A MINUTE! | ||
| There are 4 digits in the first number and only 2 in the second one! | ||
| So? | ||
| Don't all the numbers have to have the same number of places | ||
| on the right side of the decimal point? | ||
| NO! They do not! | ||
| If it makes you feel better, you can put in zeros after the .23 | ||
| until it has as many digits as the other number. | ||
| The zeros won't change the value at all. | ||
| Now lets add: | ||
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| Subtraction works the same way: | ||
| Example: | ||
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.83 - .011 |
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| Step 1: | ||
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| Step 2: | ||
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| Step 3: | ||
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| OK, Now look at this one ... | ||
| Example: | ||
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| How do we deal with this puppy? | ||
| Remember the elevator? | ||
| This time, each floor is .1 instead of 1. | ||
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| Did you notice that the decimal didn't really change the steps at all? | ||
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copyright 2005 Bruce Kirkpatrick |
